We are studying the formation of a complex neural network that innervates the skin of embryonic zebrafish. Rohon-Beard cells make an extensively branched projection pattern into the periphery. We are trying to determine the rules that regulate that projection pattern: for instance, we suspect that there must be a fine balance of attraction and repulsion between arrays of growing axons to prevent either collapse of the net into an adhesive knot or restriction of the axons into non-crossing domains. 8-31-96